Deal closed a few months ago and I'm preparing to work on a rehab deal with them in 2020. 

Then, once I have that information/proposal/etc. prepared, how should I approach investors?

Most are actually pretty helpful if you reach out and ask questions in advance vs being hostile when they make you jump through hoops completing applications and preparing for the P&Z hearing.

How long did it take and is there anything I should prepare for? 

I'm in the process of testing out Innago.

Concessions This is another monster that can decimate your cash flow if you're not prepared for it and don't underwrite your deal correctly going in.

It's important to educate yourself on how to prevent it from happening, and then being prepared to act quickly and decisively if it does happen.The problem is pervasive enough in Cleveland that a Google search turned up a lot of news articles, helpful blogs, and other resources.

D2S is great too, just know it's more work and will take more time refining your scripts and motivated seller list criteria, doing split testing, negotiating, and taking phone calls often.

Excited to start once my preparation meets the right deal.

Seems to be the trend so do our best to fight it but be prepared to pivot as required.